Preparation of 157nm transmitting barium fluoride crystals with permeable graphite
US7276219B2 · kind B2 · utility
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3References
6Claims
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Assignee
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Key dates
| Filing date | Nov 5, 2004 |
| Grant date | Oct 2, 2007 |
| Priority date | — |
| Expiry date | Apr 29, 2025 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC30B29/12
- WIPO fieldSurface technology, coating
- WIPO sectorChemistry
Abstract
The present invention is directed to a method of making large diameter metal fluoride sungle crystals that can be used in optical lithograpby systems, for example, excimer laser that operate below 200 nm. In addition, the invention is directed to metal fluoride single crystals suitable for use in such lithographic ststems, such fluoride crystals having a internal transmission of ≧99.9% at 193 nm and ≧99.0% at 157 nm.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.